In a telecommunication network, providing a QoS to packets associated with a particular service, or with a component of a service, involves subjecting the flow of packets to a common packet-forwarding treatment. In this context, a bearer is defined as an aggregate of one or more flows, such as for example Internet Protocol (IP) flows, relating to one or more services or service components. A bearer carries packets subjected to the same packet-forwarding treatment. The provision of a desired or contracted QoS is enabled by the bearer, both at the user plane and control plane level. If two sets of packets require different packet-forwarding treatments, more than one bearer is required. The binding of uplink flows to a bearer is typically performed by the terminal device, such as for example a user equipment (UE). The binding of downlink flows to a bearer is typically performed by a network node, such as for example a packet data network (PDN) gateway (PDN-GW).
The initial connection, or initial attachment, of a terminal device to a network usually involves the provision of a default bearer established based on subscription data. For some type of accesses, the default bearer is always on. A decision may be taken by the network, either at the time of the initial attachment or later, to establish a dedicated bearer to carry traffic requiring a specific packet-forwarding treatment. The default bearer is used to carry all the traffic which is not carried by a dedicated bearer.
It is desirable for network operators to be able to reliably provide services and service components to users, while taking into account the potential need to subject the traffic associated with a service or a service component to a specific packet-forwarding treatment, such as for example a specific QoS.